Influence of acute salinity stress on the immunological and physiological response of Penaeus monodon to white spot
syndrome virus (WSSV) infection was analysed. P. monodon maintained at 15‰ were subjected to acute salinity changes to 0‰
and 35‰ in 7 h and then challenged orally with WSSV. Immune variables viz., total haemocyte count, phenol oxidase activity
(PO), nitroblue tetrazolium salt (NBT) reduction, alkaline phosphatase activity (ALP), acid phosphatase activity (ACP) and
metabolic variables viz., total protein, total carbohydrates, total free amino acids (TFAA), total lipids, glucose and cholesterol were
determined soon after salinity change and on post challenge days 2 (PCD2) and 5 (PCD5). Acute salinity change induced an
increase in metabolic variables in shrimps at 35‰ except TFAA. Immune variables reduced significantly (Pb0.05) in shrimps
subjected to salinity stress with the exception of ALP and PO at 35‰ and the reduction was found to be more at 0‰. Better
performance of metabolic and immune variables in general could be observed in shrimps maintained at 15‰ that showed
significantly higher post challenge survival following infection compared to those under salinity stress. Stress was found to be
higher in shrimps subjected to salinity change to lower level (0‰) than to higher level (35‰) as being evidenced by the better
immune response and survival at 35‰. THC (Pb0.001), ALP (Pb0.01) and PO (Pb0.05) that together explained a greater
percentage of variability in survival rate, could be proposed as the most potential health indicators in shrimp haemolymph. It can be
concluded from the study that acute salinity stress induces alterations in the haemolymph metabolic and immune variables of
P. monodon affecting the immunocompetence and increasing susceptibility to WSSV, particularly at low salinity stress conditions

Aquaculture farms, particularly in Southeast Asia are
facing severe crisis due to increasing incidences of
White Spot Syndrome Virus (WSSV). Actinomycetes
have provided many important bioactive compounds of high prophylactic and therapeutic value and are
continually being screened for new compounds. In this
communication, the results of a study made to determine
the effectiveness of marine actinomycetes against the white spot disease in penaeid shrimps are presented.
Twenty-five isolates of actinomycetes were tested for
their ability to reduce infection due to WSSV among
cultured shrimps. When these actinomycetes were
made available as feed additives to the post-larvae of
the black tiger shrimp Penaeus monodon for two weeks and challenged with WSSV, the post challenge survival
showed variations from 11 to 83%. However, six
isolates have shown to be the most potential candidates
for further study.

Fenneropenaeus indicus could be protected from white spot disease (WSD) caused by
white spot syndrome virus (WSSV) using a formalin-inactivated viral preparation (IVP) derived from
WSSV-infected shrimp tissue. The lowest test quantity of lyophilized IVP coated onto feed at 0.025 g–1
(dry weight) and administered at a rate of 0.035 g feed g–1 body weight d–1 for 7 consecutive days was
sufficient to provide protection from WSD for a short period (10 d after cessation of IVP administration).
Shrimp that survived challenges on the 5th and 10th days after cessation of IVP administration
survived repeated challenges although they were sometimes positive for the presence of WSSV
by a polymerase chain reaction (PCR) assay specific for WSSV. These results suggest that F. indicus
can be protected from WSD by simple oral administration of IVP

The objective of the study was to find out a natural way to fight white spot syndrome virus (WSSV) in cultured
shrimps, as the present scenario necessitated an organic remedy for the devastating pathogen in crustaceans.
Under this research programme seven mangrove plants were collected, identified and aqueous extracts
screened for their protective effect on the giant tiger shrimp Penaeus monodon against WSSV. The
experimental design consisted two modes of application, such as exposure of the virus to the extract and
injection challenge, and oral administration of the extract coated feed followed by oral challenge. All
experimental animals were monitored through a nested diagnostic PCR analysis. Of the seven mangrove
extracts screened aqueous extract from Ceriops tagal imparted total protection to shrimp from WSSV when
challenged by both methods. Shrimps administered with the aqueous extract from C. tagal were devoid of
virions. The HPLC fingerprint of the aqueous extracts from C. tagal showed more than 25 peaks and 7 of them
were larger and well separated. Preliminary phytochemical analysis revealed the presence of alkaloids,
flavonoids, polyphenolics, cardiac glycosides, saponins and sterols. The study indicated suitability of the
aqueous extract of C. tagal as a possible prophylaxis for WSSV infection in shrimp. This is the first report on the
anti WSSV property of the mangrove plant C. tagal

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Yeasts are ubiquitous in their distribution and populations mainly depend on the
type and concentration of organic materials. The distribution of species, as well as
their numbers and metabolic characteristics were found to be governed by existing
environmental conditions. Marine yeasts were first discovered from the Atlantic
Ocean and following this discovery, yeasts were isolated from different sources, viz.
seawater, marine deposits, seaweeds, fish, marine mammals and sea birds. Nearshore
environments are usually inhabited by tens to thousands of cells per litre of
water, whereas low organic surface to deep-sea oceanic regions contain 10 or fewer
cells/litre. Aerobic forms are found more in clean waters and fermentative forms in
polluted waters. Yeasts are more abundant in silty muds than in sandy sediments.
The isolation frequency of yeasts fell as the depth of the sampling site is increased.
Major genera isolated in this study were Candida, Cryptococcus, Debaryomyces and
Rhodotorula. For biomass estimation ergosterol method was used. Classification and
identification of yeasts were performed using different criteria, i.e. morphology, sexual
reproduction and physiological/biochemical characteristics. Fatty acid profiling or
molecular sequencing of the IGS and ITS regions and 28S gene rDNA ensured
accurate identification.

Aim: To develop a new medium for enhanced production of biomass of an
aquaculture probiotic Pseudomonas MCCB 103 and its antagonistic phenazine
compound, pyocyanin.
Methods and Results: Carbon and nitrogen sources and growth factors, such as
amino acids and vitamins, were screened initially in a mineral medium for the
biomass and antagonistic compound of Pseudomonas MCCB 103. The selected
ingredients were further optimized using a full-factorial central composite
design of the response surface methodology. The medium optimized as per the
model for biomass contained mannitol (20 g l)1), glycerol (20 g l)1), sodium
chloride (5 g l)1), urea (3Æ3 g l)1) and mineral salts solution (20 ml l)1), and
the one optimized for the antagonistic compound contained mannitol (2 g l)1),
glycerol (20 g l)1), sodium chloride (5Æ1 g l)1), urea (3Æ6 g l)1) and mineral
salts solution (20 ml l)1). Subsequently, the model was validated experimentally
with a biomass increase by 19% and fivefold increase of the antagonistic
compound.
Conclusion: Significant increase in the biomass and antagonistic compound
production could be obtained in the new media.
Significance and Impact of the Study: Media formulation and optimization are
the primary steps involved in bioprocess technology, an attempt not made so
far in the production of aquaculture probiotics.

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Marine yeasts (33 strains) were isolated from the
coastal and offshore waters off Cochin. The isolates
were identified and then characterized for the utilization
of starch, gelatin, lipid, cellulose, urea, pectin,
lignin, chitin and prawn-shell waste. Most of the
isolates were Candida species. Based on the
biochemical characterization, four potential strains
were selected and their optimum pH and NaCI
concentration for growth were determined. These
strains were then inoculated into prawn-shell waste
and SCP (single cell protein) generation was noted in
terms of the increase in protein content of the final
product.